Base metal alloy



Patented June 25, 1940 UNITED STATES 2,205,888 \l BASE METAL annoy Charles J. Koebel, Detroit, Mich, assignor, by mesne assignments, to Koebel Diamond Tool 00., Detroit, Mich, a corporation of Michigan 7 No Drawing. Original application June 30, 1930,

Serial No. 462,485. Divided and this application January 12, 1932. Serial No. 586,238

1 Claim.

This invention relates generally to alloys and has more particularly referenceto alloysused for the purpose of setting diamonds, carbonados or the like. The present application is a division 5 of application Ser. No. 462,485, filed June20, 1930,

now Patent No. 1,848,182, Mar. 8,1932.

Diamonds are now being used to a very great extent in the industrial arts, examples of such use being: as dressing tools for grinding wheels; as core bits for rock drilling; as saw teeth; and as dies for drawing wire. Manifestly their use for such purposes as have been indicated above, imposes strains and stresses of considerable magnitude upon the diamonds and their mountings, Unless the diamond is held very firmly in its mounting, it may work loose and become lost or, if not lost, it will quickly destroy its own setting and will become useless as a tool. It is the practice now to use relatively large stones and 20 to reset them when they work loose. Repeated resettings however, especially if heat be used, have a very deleterious effect upon the diamond, and it is therefore not always possible to reset 2. diamond as it may have become injured or its 25 skin may have been destroyed or penetrated, by adjacently mounted diamonds or otherwise, to such an extent that it is no longer serviceable in the task for which it is intended. I It is the main object and feature of this in- 30 vention to produce a base metal alloy capable of being sintered at a temperature below that of the critical point at which the desirable qualities of the diamond are adversely aflfected and which- The'following formula of an alloy, successfully used, is given:

Per cent .Molybdenum 28 0 Coba 48 Copper I 27.75 Iron The proportions given are by weight and not by volume. The materials of which the alloy is composedare reduced to powder form and thoroughly mixed, a slight amount of paraiilne being added, before the diamond is imbedded therein. Molybdenum is chosen because, apparently, it imparts a hardness of high degree to the finished setting. The function of the cobalt appears to be that of rendering the alloy wettable with respect to the diamond. The copper seems to prevent the alloy from robbing the carbon.

The diamond or diamonds are imbedded in a mass of the comminuted alloy of the character described, after which said alloy'is subjected to pressure so as to shape it. The pressure used may be from thirty to forty tons to the square inch, and causes the mass to be shaped into a body capable of substantially maintaining its form when pressure is thereafter removed. The shaped body is then introduced into a furnace and heated to a temperature below the critical point above mentioned, say 1245 degrees centigrade, said furnace being devoid of oxygen, after which the mass is cooled in a chamber also devoid of diamond of oxygen. If desired, there may be a preliminary During the heating, the body has shrunk but slightly but has become av coherent solid sintered mass in which the diamonds are imbedded in the same relative position they originally occupied, andcit would therefore seem that the effective coeillcient of expansion of the alloy approximates that of the diamond.

I claim:

As a new article of manufacture, a setting for diamonds composed of an alloy including molybdenum, approximately twenty-six percent, copper approximately twenty-eight percent and cobalt approximately forty-six percent.

CHARLES J. KOEBEL. 

